Transcript The scientific process in Psychology

Today you will
• Define and distinguish between questions,
aims and hypotheses in psychological
research
• Identify appropriate aims and hypotheses to
answer research questions
• Generate research aims and hypotheses
from research questions
• Understand the difference between a null and
alternative hypothesis
The scientific process in Psychology
Questions about
human behaviour
Why do people
conform to gender
stereotypes?
General research aims
Investigate whether
stereotypes are
reinforced by media eg
TV programmes
Specific and testable
predictions
(hypotheses)
Female characters in
Eastenders will be
portrayed in typically
feminine roles more than in
typically masculine roles
A research question:
• Why do people eat chocolate?
• List some possible answers to this
question
• This is a very broad question so for now
let’s focus on just one possible
explanation
• What would be a suitable aim for a
study?
Types of aims
• Descriptive
• Relational
• Causal
• What is the difference?
• Which one do we want?
A research scenario
• We’ve established that our aim is to investigate
the effect of chocolate consumption on
happiness
• Which of these is the IV and which is the DV?
– IV: Chocolate (the variable that is manipulated)
– DV: Happiness (the variable that is measured)
• Imagine you’ve obtained a sample of two groups
of people:
– 1: eats one bar of chocolate every day
– 2: never eats chocolate
• You are going to measure happiness on a selfreport rating scale
• What do we do next?
Hypotheses
• An hypothesis is a testable statement that
proposes a relationship between two
variables
• Hypotheses come in two forms:
– H1 : the alternative (research/experimental)
– H0 : the null
• Hypotheses should be operationalised – this
means you need to state:
– Conditions of the IV
– How the DV is being measured
– The predicted relationship between the two
H1: The alternative hypothesis
• This predicts what we think will happen
• In our study, we think that chocolate might
increase happiness, so our hypothesis could
state:
• “Participants in the chocolate condition will
have higher scores on a self-report happiness
rating scale than those in the non-chocolate
condition”
• Has this hypothesis been operationalised?
– Can you tell the conditions of the IV, the
measurement of the DV and what relationship is
being predicted?
What if our prediction is wrong?
• Remember, in Psychology we never say
we’ve proved or disproved anything; we can
only accept or reject our hypotheses
• If our results do not support our alternative
hypothesis then we would have to reject H1
• We would then accept the null hypothesis
instead
H0: The null hypothesis
• This essentially predicts that there will be no
relationship between the variables:
• “There will be no difference in participants
happiness scores on a self-report rating scale
between the chocolate and no chocolate conditions
or any differences found will be down to chance”
• Note the last part of this – we’re still allowing for the
possibility that the results could have happened by
chance anyway
Directional or non-directional?
• Hypotheses need to predict that there is a
relationship between variables but do not
necessarily have to say what the relationship is
• For example, we might believe that chocolate
consumption affects happiness but aren’t sure
whether it will increase or decrease happiness
• In this case we would make our hypothesis nondirectional eg:
• “There will be a difference in participants scores on
a self-report happiness rating scale between those
in the chocolate condition and those in the nonchocolate condition”
What if we’re not doing an experiment?
• A hypothesis just predicts a relationship,
this doesn’t have to mean a causal one
• Correlational hypotheses simply state
that there is a link between two
variables
• Why do some students get better
grades than others?
Correlational research
Question:
Why do some students get better grades than
others?
Aim:
To investigate the relationship between working
habits and academic achievement
Hypothesis: There will be a correlation between the mean
number of hours of hours spent studying per
week and the UMS marks achieved in an exam.